System for water and food safety testing

ABSTRACT

A system for testing for environmental contaminants using strip tests, obtaining and uploading images of strip tests into a processor, associating a test data set including location, time, and date of test with each image, determining a test result through computational analysis of each image, and storing and reporting test results and data sets.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 61/614,431, entitled “SYSTEM FOR WATER AND FOOD SAFETYTESTING” filed on Mar. 22, 2012, which is hereby incorporated byreference in its entirety for all purposes.

BACKGROUND OF THE INVENTION

News reports about fertilizer, pesticides and pathogens in our streams,drinking water and food have become commonplace. Recently Congresspassed the Food Safety Modernization Act. Water quality boards andgovernment groups across America are passing laws to monitor waterpollution from farm runoff. Beaches along the Atlantic and Pacificshores are often closed due to E coli contamination from faulty sewagetreatment.

To determine how severe the problem is and how to react, data is neededon the severity of the pollution, location and time. First, an accuratemeasurement of the pollutant concentration in the environment needs tobe made and compared to limits set by governing bodies. Most often, thelocation and time of a data point is also crucial.

We expect governmental entities such as the US Department of Agricultureand EPA to set safe limits, monitor, and enforce these limits.Historical methods of testing rely on environmental engineeringcontractors and labs using expensive capital equipment. Test programstake months to be completed and published. The USDA publishes datashowing fresh produce is safe to eat while the Environmental WorkingGroup publishes the “Dirty Dozen” list of contaminated produce eachyear.

Government budgets for testing have been reduced during the recession.People turn to the internet with questions about food and waterpollution. A multimillion dollar industry has emerged to provide quick,inexpensive strip tests; sold to worried citizens. Hundreds of low-cost,simple tests are available to detect levels of arsenic, lead, nitrate,E. coli, etc. in the water and food. Most of these tests employdisposable test strips that change color based on the level ofcontaminant in the sample solution.

Single use disposable strip tests, which give a qualitative indicationof analyte concentration based on color, have been commerciallyavailable for over 30 years. These strips change color when exposed to atarget analyte and are then matched against a card containing a set ofcolor squares with numbers indicating concentration of pollution. Theuser can determine the approximate level of analyte in the sample byholding the strip up against the card, identifying the color sampleclosest to the color of the exposed strip and writing down the number.Common strip tests measure pH in of water quality, chlorine in pools andspas, pesticides in drinking water; E coli in drinking water; etc. Striptests usually include a plastic substrate; a porous layer, acalorimetric indicator impregnated in the porous layer and a Color Bar.Examples of disposable strip tests are found in U.S. Pat. Nos. 3,006,735and 5,620,658. Technology from the medical diagnostic industry is alsosold into this marketplace. LFIA (Lateral Flow ImmunochromagraphicAssay) technology usually generates two color lines on a strip test. Oneline tells if the test is working; the second is an indicator of whetherthe analyte the test is meant to detect is above a threshold level. Themost common example is the pregnancy test “sticks.” Companies also sellE coli tests in this format.

There is a pervasive sentiment that the risk to our health fromindustrial chemicals in our food and water is increasing each year.Warnings and assignment of blame fill our newspapers and blogs. Ourfarms and industries are our livelihood, committed to selling safe,quality products. Our water quality agencies, the FDA, USDA and EPA workto keep us safe. They struggle with pollution issues covering millionsof square miles, hundreds of thousands of farms and millions of shippingcontainers. Citizens and cash strapped government agencies need reliabledata to monitor and solve problems. Accurate, timely, mapped data iscritical but is not available for farm runoff, E coli on beaches andpesticide on imported produce.

Low-cost strip tests could supply data quickly, but there are fourprimary problems limiting their value. First, these tests can onlyprovide subjective “qualitative” results since each tester is requiredto match the exposed test strip's color to one of the color samples onthe color card. Variable lighting conditions, color sensitivity and evenvisual acuity can affect testers' judgment. Level of training is also aproblem. Further, the limited number of color samples provided on acolor card defines the test's precision, i.e. how does one evaluate alight yellow test strip sample that falls between the lighter yellowcolor sample marked 0.2 mg/l or nearer to the darker yellow color samplemarked 0.3 mg/l? As a result, most government agencies do not use thesetypes of tests.

A second problem arises in storing the test for later validation andreview. The color on most of the test strips fades quickly, thus cannotbe reliably stored.

The third problem with strip tests is that the test is not associatedwith a time, date or place; or the person doing the test. Responsibilityfor the polluted water is often determined by the location of themeasurement. The transient nature of pollution problems requires carefultime based records. Should the test results be used to assign blame fora pollution problem, location, time, date and tester identification isneeded.

The fourth problem is the need to do multiple tests at the same timeover a large area. Surface water contamination can cover many miles of ariver. Mercury contamination in a bay or ocean can cover hundreds ofsquare miles of area. E coli problems on a beach near a sewer outfallcan cover miles. Test location allows the mapping necessary to monitorand enforce pollution laws.

These problems limit the evidential value of strip tests to courts andgovernmental agencies. Citizen groups who use strip tests to lodge acomplaint or request remediation of a pollution problem may find theirefforts blocked by opponents who point out some of these fourlimitations. In a publicized example, parents sued their school districtto remove lead-contaminated paint from their children's school but noaction was taken when the school demonstrated how often the testsyielded false positive results from the colorimetric strip test theybought on the internet.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a Back Card and Test Strip in accordance withone embodiment of the invention.

FIG. 2 is a series of screen shots which illustrate a sequence of stepswhich can be employed in the user interface disclosed herein as oneembodiment of the inventive system.

FIG. 3 is an example of a calibration curve which may be generated byone embodiment of the system described herein.

FIG. 4 is a diagram which illustrates the roles of a tester, a user, amobile application, and a processor in accordance with one embodiment ofthe invention disclosed herein.

DETAILED DESCRIPTION

Disclosed herein are methods, software, and devices which augment theuse of colorimetric test strips to enable users to automatically analyzeand record standardized test results and other data associated with atest event such as location and time.

Test strips, which have been validated and calibrated through iterativetesting procedures, are used in this method. When a tester uses a teststrip to perform a test, the test strip is placed against the Back Cardand photographed following instructions in the software application onthe smart phone The application then transmits the photograph to theonline server via a broadband or WiFi connection to the phone. Theapplication also transmits the GPS location of the test, time test takenand identification of the test phone. Computational image analysissoftware is then used to assign a value to that test result, and thatvalue, the location, and the time and date of that test can then bewirelessly and automatically sent back to the smart phone where itoriginated from. Aggregate data can be presented using a web portalwhich will allow testers and users to view maps of data and shareaggregated test data in the form of maps or reports.

Referring to FIG. 1, Test strips 10 are typically elongated plasticstrips with one or more absorbent, chemically treated pads 12 locatednear one end. At least one absorbent pad is chemically treated to changecolor to indicate the concentration of a contaminant when immersed in atest solution. An additional chemically treated pad may be present todetermine whether testing protocols have been followed, for examplewhether the test strip has been immersed in the test solution for anappropriate amount of time. Commercially available colorimetric teststrips can be used. For example, the WaterWorks Nitrate and Nitrite PartNo. 480009 from Industrial Test Systems is appropriate for use in theinventive methods. However, any test strip used in this inventive methodshould be calibrated to yield reliable data when subjected tocomputational image analysis.

The Back Card 14 should be flat for ease of photography in the fieldusing a smart phone. It should have a matte finish. It features a colorbar 16, which is a graphic element printed on the Back Card consistingof a series of color squares which relate square color to contaminantconcentration. Optionally present on the Back Card is a test squaregraphic 18, which can be a dark shape outlining the color bar, and whichpermits the inventive system to determine through computational imageanalysis whether the user has placed the test strip in the correctposition. Optionally, bar codes 20 or other identifying information maybe present on the back card so that test strip and Back Cardidentification information may also be processed digitally andaggregated along with test results, time, and location data. Theinventive system may catalog individual test strips that are approvedfor use with the system, and may prevent use of an unauthorized teststrip, re-use of a single test strip, or use of a single test inmultiple locations by rejecting any such test data submitted.

The test strips are immersed into a sample of the test solution, forexample the water that will be tested, in accordance with instructionswhich can be provided digitally over the web or with the test stripsand/or back card. Once the test has been performed, the test strip ispositioned against the back card, and the tester photographs the teststrip and the back card.

A smart phone or other device with a processor and an operation systemcompatible with custom smart phone applications and capable of taking aphotograph, and recording data such as time, date and location, can beused to photograph the test strip and the Back Card. An application thatis either loaded onto the device or is operated by the device can guidethe user's actions when performing the test, associate a data set withthe image, and upload both for processing. For example, the applicationmay provide information, including real time, step by step instructionsfor testing. The application may assist a tester in timing immersion ofthe test strip in the testing medium by providing alarms, a visual orauditory timer, or other signals. The application may also quantify thetime which has elapsed between immersion or removal of the test strip inthe testing medium and the photographing of the test strip and backcard.

Referring to FIG. 2, the application will assist the User when taking aphotograph with an active template or other digital alignment tool thatcorresponds to features on the back card or test strip, such as thecolor bar and test square on the back card. The user moves the phoneinto position 24, such that the graphic elements on the Back Card alignwith the Active Template. Alignment with the Active Template 26 assuresthe test results 28 are accurate.

Once a photograph is taken, the photograph is uploaded into the onlinesystem, where computational image analysis is used to derive a numericalvalue corresponding to the color present in the image of the absorbentpad on the test strip. The software performing this analysis can becalibrated and validated using the colors present in the color bar inthe same photograph. This computational analysis, calibrated andverified, results in much more consistent, and less subjective, readingof the test strips. The device application also displays testinginformation such as the amount of time that elapsed between thebeginning of the test and the photographing of the test strip, the timeand date of the test, and the geographic location of the test. With orwithout additional user approval or input, the device level applicationthen uploads that information along with the photograph to the systemfor analysis. In addition, the Application reviews the photograph forproblems and alerts the User with with error messages, within theapplication, on the smart phone screen (e.g. low light, poor alignment,etc).

The test data and photograph are uploaded into a processor located on aserver which is connected to the internet. The processor receives imagesand data and metadata from devices used in testing, and generates a dataset from and associated with each photograph. The processor alertsdevice users of errors, and creates and stores verification if alltesting protocols are observed by the user. The processor also operatesor is used in conjunction with one or more databases, which storephotographs, test results, test data, information about test kits, anderrors, verification, and other information. The processor generates andstores a data set from each photograph. The processor aggregates testresults and data, and can be used to provide reports which aggregatedata into forms that provide for aggregate analysis such as maps showingthe times and results of tests. The processor interfaces with a webportal which can work in conjunction with or instead of an applicationloaded onto a mobile device.

An application or web portal can be accessed using login data thatidentifies users with particularity. A web page associated with theprocessor may also sell test kits and other associated products.Information from testing may be available for download in aggregate formor from individual tests.

When the processor receives a photograph and associated data, it firstperforms a series of image analysis steps to locate the color bars andtest square. Next, a computational script determines the luminance(candelas per square meter (cd/m2) for each square in the Color Bar andthe Test Square. This data is linked to the sample identification numberand stored on the processor. Software uses the digital data from theimage analysis and applies mathematical image analysis algorithms todetermine the test result.

In one embodiment, the processor determines the test result as follows.First the color bar data is used with stored data on test calibration tocreate a conversion function for each test. Next, the data for theluminance of the test square is related to the calibration curve todetermine the initial test result. Then, mathematical algorithms areapplied to improve accuracy and precision and determine the final testresult. Next the test result is stored, linked to the sampleidentification, in the processor. Software reviews the location of thecolor bar on the color bar graphic 22, shown in FIG. 1, and the testsquare 12 on the test square graphic 18, and generates error messages ifthey are not present. The black square of the color card graphic islocated and analyzed to determine if the color card is present. Theblack square of the test square graphic is located and analyzed todetermine if the Test Strip 10 is present.

The optional single or two-dimension bar code 20 on the back card 14, ifpresent, will be part of the photograph sent by the application, andcontains data about the project and the identity of the test and thetest strip kit OEM manufacturer.

A water quality agency which has received reports that there is highnitrogen concentration in a river, possible from fertilizer run off fromfarms along the river, can employ testers to use the inventive systemand methods to determine the nitrate concentration at several locationsalong river. The testers could use one embodiment of the inventivesystem and methods as follows:

1) Login and create a project on the Web Portal.

2) Point and click on interactive map to designate sample sites alongthe river.

3) Select the Nitrate Test from the online list.

4) Follow online prompts to purchase the test

5) Receive Test Kits

-   -   a) Test Strips and Back Card and Printed Instructions    -   b) Clean sample collection bottle

6) Download test application and load onto smart phone

7) Print out project specific map

8) At each test location along the river:

-   -   a) Review Printed Instructions    -   b) Start Application    -   c) Collect sample in bottle    -   d) Dip Test Strip in bottle    -   e) Place Test Strip on Back Card    -   f) Follow instructions in application and obey prompts to        complete the test and to capture an image    -   g) Approve image to send to the system. The application then        sends the image to the system along with GPS location        information, date, time, photo of the sample location,        confirmation that the protocols were followed, etc.    -   h) Review Results. If Error, capture an additional image.

9) User access Web Portal on a PC to generate test reports and sharedata.

Additionally, in other embodiments, the processor may compare the colorbar data from each image sent to processor to stored color card imagedata to determine if incident light on back card during tests was belowoptimum and generate an error message to transmit to smart phone. It mayalso compare the Color Bar data from each image sent to Processor tostored Color Card image data to determine if the Color Bar is out offocus and generate an error message and transmit to smart phone.

In other embodiments, the system may also error check image acceptanceon smart phone when connection to the System is not available byutilizing software that reviews the location of the Color Bar on theColor Bar Graphic and the Test Square on the Test Square Graphicutilizing image analysis software resident in the application on thesmart phone. The processor may also error check image acceptance onsmart phone when connection to the processor is not available by addingadditional graphic elements to the printed Back Card that can beanalyzed on image analysis software resident in the Application on thesmart phone.

The system may protect against counterfeit Back Cards by printing uniquegraphic elements on approved back cards that are recognized by imageanalysis software resident in the application on the smart phone.

Additionally, the system may be operated to create improved calibrationalgorithms utilizing data from laboratory testing. This can be done bycreating stock solutions with varying known concentrations of targetcompound across the range covered by Strip Test, then testing the stocksolution using test strips and using the application to upload picturesof those test strips and Back Cards. The accuracy of the calibrationcurve, an example of which is shown in FIG. 3, which is used in thecomputational image analysis process can then be improved using the testresults from the stock solutions. Calibration test data can beincorporated into the bar code on the back card and can form part of thedata file associated with each test image.

Additional variations include the following. EPA maximum limits for atest compound can be added to test strips in order to show results atleast in part as pass/fail. The Back Cards can be incorporated into teststrip packaging. The application can prompt a user to take multiplepictures of a test strip at given time intervals in order to improveaccuracy. Multiple test strips can be photographed in a single image.

The web portal can include training and certification procedures, andthe completion of training and certification can be associated with agiven use identifier and can be certified or recorded. The system canalso capture user specific data such as the number of tests performed,aggregate test results, and the number of errors associated with thatuser's activity.

The test may include the imaging of a bar code or other identifierplaced on a water bottle sample. The system would thereby record dataregarding where and when the water sample was collected and the testresults when the sample was collected.

Finally, the application may respond to a test performed where no GPS ordata transfer is available by storing the image and data for uploadlater.

One embodiment of the system disclosed herein is illustrated in FIG. 4.A tester 112 gets test instructions 114 from a mobile device application116. The tester uses those instructions to perform a test 118 andphotograph 120 the test results. The mobile device 130 sends test data121 to the system, which then processes it and sends results back to themobile device for review 122 by the Tester. The results and data arestored 140 on the server 110, and a User 180 can log on 150 to theserver, view test results 160, and download data 170.

The terms and expressions which have been used in this specification areintended to describe the invention, not limit it. The scope of theinvention is defined and limited only by the following claims.

What is claimed is:
 1. A method of generating a test result whichmeasures the presence of a contaminant in a test solution, comprising:a) immersing a strip test in said test solution, said strip test havingan absorbent pad which is chemically treated to change color to indicateconcentration of a contaminant; b) removing said test strip from saidtest solution and generating a digital image of said test strip; c)generating a test data set and associated said test data set with saidimage; d) uploading said image and said test data to a first processer;and e) using software present on said central processor to generate atest result using computational analysis of said image.
 2. The method ofclaim 1 further comprising the step of transmitting said test result toa second processer in a location remote from said first processer. 3.The method of claim 1 wherein said test data comprises the time saidimage was generated and the location of a device used to generate saidimage.
 4. The method of claim 1 wherein said processor evaluatesplacement of said strip test within said image and generates andtransmits an error message if said placement does not comply withpredetermined parameters.
 5. The method of claim 2 wherein said image isgenerated by said second processor, and said second processer iswirelessly interconnected with said first processor, and said secondprocessor generates data associated with said image.
 6. The method ofclaim 1 wherein said first processor is adapted to aggregate multipletest results into one or more reports based on one or more commonalitieswithin test data sets.
 7. The method of claim 1 further comprising thestep of aligning a test square graphic located on a back card with adigital alignment tool before said image is created.